How do circuits in the stock ecu work?
#1
How do circuits in the stock ecu work?
Question for instance:
If I multi meter a pin on the ECU that typically controls my SAS pin should I see 12v at that pin when using the chassis or ecu earth as ground for the mutlimeter?(of course when that pin is active by the ecu --- not full time)
My goal is to create a circuit that when the SAS solenoid is applied will apply a voltage to trip the alt map pin. Ive done a half assed cobb job to test my theory.
I need to run a circuit from the ECU pin #4, to my alt map pin that yelds a voltage suitable for the alt map switch.
The biggest part of this system is that it must not draw enough from the pin so that its original function of actuating a 3port solenoid is lost.
If I multi meter a pin on the ECU that typically controls my SAS pin should I see 12v at that pin when using the chassis or ecu earth as ground for the mutlimeter?(of course when that pin is active by the ecu --- not full time)
My goal is to create a circuit that when the SAS solenoid is applied will apply a voltage to trip the alt map pin. Ive done a half assed cobb job to test my theory.
I need to run a circuit from the ECU pin #4, to my alt map pin that yelds a voltage suitable for the alt map switch.
The biggest part of this system is that it must not draw enough from the pin so that its original function of actuating a 3port solenoid is lost.
Last edited by 211Ratsbud; Jan 27, 2013 at 08:49 PM.
#2
Evolved Member
iTrader: (6)
What I can tell is that your system would work with a 12v to 5V circuit. The alt map input is a 5V input. ECU input's impedance is near infinite (very high), that means these inputs don't draw any significant current. Easiest would be using a map switching harness hacked for SAS 12V output, to feed the 5V ADCOF.
Last edited by domyz; Jan 28, 2013 at 08:51 AM.
#7
Evolved Member
iTrader: (6)
It would need a very simple mod in the ECU code to do that. The ECU, instead of looking ADCOF(or AutoICS) input state, could lookup the state of SAS output to switch to altmaps...
It could be as simple as changing an adress into the ROM and you'll have your switching.
I'm still learning about disassembly so I won't get into that, but I know enough to tell you that it's quite simple to do. I'm sure (for xx$ or free), one of our ECU gurus will be happy to do that for you. (mrfred,tephra,jcsbanks,phenem,mattjin, logic, l2r99gst, acamus, others)
It could be as simple as changing an adress into the ROM and you'll have your switching.
I'm still learning about disassembly so I won't get into that, but I know enough to tell you that it's quite simple to do. I'm sure (for xx$ or free), one of our ECU gurus will be happy to do that for you. (mrfred,tephra,jcsbanks,phenem,mattjin, logic, l2r99gst, acamus, others)
Last edited by domyz; Jan 28, 2013 at 05:43 PM.
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#9
It would need a very simple mod in the ECU code to do that. The ECU, instead of looking ADCOF(or AutoICS) input state, could lookup the state of SAS output to switch to altmaps...
It could be as simple as changing an adress into the ROM and you'll have your switching.
I'm still learning about disassembly so I won't get into that, but I know enough to tell you that it's quite simple to do. I'm sure (for xx$ or free), one of our ECU gurus will be happy to do that for you. (mrfred,tephra,jcsbanks,phenem,mattjin, logic, l2r99gst, acamus, others)
It could be as simple as changing an adress into the ROM and you'll have your switching.
I'm still learning about disassembly so I won't get into that, but I know enough to tell you that it's quite simple to do. I'm sure (for xx$ or free), one of our ECU gurus will be happy to do that for you. (mrfred,tephra,jcsbanks,phenem,mattjin, logic, l2r99gst, acamus, others)
You would have to re-write the code so that when you had the correct conditions for SAS activation then the ECU also switches the maps over but that's a bit more complicated than just switching maps based on the SAS output.
Andy
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